Fine needle aspiration cytology of uncommon thoracic lesions

Transthoracic fine needle aspiration biopsy provides valuable information influential in patient management, but at the same time it has introduced new interpretative problems. This paper presents some uncommon thoracic lesions, including thymoma, pulmonary hamartoma, pulmonary pseudolymphoma, typical carcinoid tumor, and spindle cell carcinoid mimicking oat cell carcinoma. Each of these cases has unique cytologic features. Since cells derived from these lesions are seen rarely or not at all in exfoliative cytology, lack of familiarity with their cytologic features may result in erroneous interpretation. Other factors contributing to the success of the needle aspiration biopsy are also discussed.